1. Field of the Invention
This invention relates to an electrophotographic image forming member used for forming an image utilization of electromagnetic waves such as ultraviolet rays, visible rays, infrared rays, X-rays, and so forth. More particularly, this invention is concerned with an improvement in an electrophotographic image forming member having a photoconductive layer which consists of a layer of an amorphous material with silicon atom as the matrix constituent atom.
2. Description of the Prior Art
Recently, there has been made known an electrophotographic image forming member, the photoconductive layer of which is constructed with amorphous material with silicon atom as the matrix constituent atom (hereinafter abbreviated as "a-Si") - vide: for example, U.S. Pat. No. 4,225,222, U.S. Pat. No. 4,265,991, laid-open Japanese patent application No. 55-69149, etc. Such image forming member has various advantages such that it causes no environmental pollution, and has good heat-resistance, high sensitivity, durability, and so forth.
Amorphous silicon (a-Si) has heretofore been studied mostly from the standpoint of the photoconductive material for the so-called "solar battery", and its study and research as a constituent material for the photoconductive layer of the electrophotographic image forming member have just been started, hence there still remain with it several points of problem to be solved from the practical aspects.
In the first place, the deposited film of a-Si has a large stress which causes it to be readily exfoliated from a base member or substrate. In particular, when the a-Si deposited layer is to be formed on a curved surface of a drum-shaped substrate made of aluminum, etc. for the electrophotography, this peeling phenomenon is considerable.
In the second place, there has so far been hardly available the material for the substrate capable of forming a predetermined favorable electrical contact with the a-Si deposited layer, on account of which movement of electric charges through the interface between the substrate and the a-Si deposited film cannot be smooth at the time of the latent image forming process.
In the third place, sensitivity of the a-Si deposited layer to light in a long wavelength region close to the near-infrared region of the visible light is considerably lower than that to light in a shortwavelength region of the visible light.